Improve macro hygiene
This commit improves hygiene and formatting of macro definitions
throughout the library. Specifically:
- It adds brackets around parameters to avoid unintended
interpretation of arguments, e.g. due to operator precedence.
- It adds uses of the `do { ... } while( 0 )` idiom for macros that
can be used as commands.
diff --git a/library/des.c b/library/des.c
index ca9e071..8a33d82 100644
--- a/library/des.c
+++ b/library/des.c
@@ -257,50 +257,57 @@
/*
* Initial Permutation macro
*/
-#define DES_IP(X,Y) \
-{ \
- T = ((X >> 4) ^ Y) & 0x0F0F0F0F; Y ^= T; X ^= (T << 4); \
- T = ((X >> 16) ^ Y) & 0x0000FFFF; Y ^= T; X ^= (T << 16); \
- T = ((Y >> 2) ^ X) & 0x33333333; X ^= T; Y ^= (T << 2); \
- T = ((Y >> 8) ^ X) & 0x00FF00FF; X ^= T; Y ^= (T << 8); \
- Y = ((Y << 1) | (Y >> 31)) & 0xFFFFFFFF; \
- T = (X ^ Y) & 0xAAAAAAAA; Y ^= T; X ^= T; \
- X = ((X << 1) | (X >> 31)) & 0xFFFFFFFF; \
-}
+#define DES_IP(X,Y) \
+ do \
+ { \
+ T = (((X) >> 4) ^ (Y)) & 0x0F0F0F0F; (Y) ^= T; (X) ^= (T << 4); \
+ T = (((X) >> 16) ^ (Y)) & 0x0000FFFF; (Y) ^= T; (X) ^= (T << 16); \
+ T = (((Y) >> 2) ^ (X)) & 0x33333333; (X) ^= T; (Y) ^= (T << 2); \
+ T = (((Y) >> 8) ^ (X)) & 0x00FF00FF; (X) ^= T; (Y) ^= (T << 8); \
+ (Y) = (((Y) << 1) | ((Y) >> 31)) & 0xFFFFFFFF; \
+ T = ((X) ^ (Y)) & 0xAAAAAAAA; (Y) ^= T; (X) ^= T; \
+ (X) = (((X) << 1) | ((X) >> 31)) & 0xFFFFFFFF; \
+ } while( 0 )
/*
* Final Permutation macro
*/
-#define DES_FP(X,Y) \
-{ \
- X = ((X << 31) | (X >> 1)) & 0xFFFFFFFF; \
- T = (X ^ Y) & 0xAAAAAAAA; X ^= T; Y ^= T; \
- Y = ((Y << 31) | (Y >> 1)) & 0xFFFFFFFF; \
- T = ((Y >> 8) ^ X) & 0x00FF00FF; X ^= T; Y ^= (T << 8); \
- T = ((Y >> 2) ^ X) & 0x33333333; X ^= T; Y ^= (T << 2); \
- T = ((X >> 16) ^ Y) & 0x0000FFFF; Y ^= T; X ^= (T << 16); \
- T = ((X >> 4) ^ Y) & 0x0F0F0F0F; Y ^= T; X ^= (T << 4); \
-}
+#define DES_FP(X,Y) \
+ do \
+ { \
+ (X) = (((X) << 31) | ((X) >> 1)) & 0xFFFFFFFF; \
+ T = ((X) ^ (Y)) & 0xAAAAAAAA; (X) ^= T; (Y) ^= T; \
+ (Y) = (((Y) << 31) | ((Y) >> 1)) & 0xFFFFFFFF; \
+ T = (((Y) >> 8) ^ (X)) & 0x00FF00FF; (X) ^= T; (Y) ^= (T << 8); \
+ T = (((Y) >> 2) ^ (X)) & 0x33333333; (X) ^= T; (Y) ^= (T << 2); \
+ T = (((X) >> 16) ^ (Y)) & 0x0000FFFF; (Y) ^= T; (X) ^= (T << 16); \
+ T = (((X) >> 4) ^ (Y)) & 0x0F0F0F0F; (Y) ^= T; (X) ^= (T << 4); \
+ } while( 0 )
/*
* DES round macro
*/
-#define DES_ROUND(X,Y) \
-{ \
- T = *SK++ ^ X; \
- Y ^= SB8[ (T ) & 0x3F ] ^ \
- SB6[ (T >> 8) & 0x3F ] ^ \
- SB4[ (T >> 16) & 0x3F ] ^ \
- SB2[ (T >> 24) & 0x3F ]; \
- \
- T = *SK++ ^ ((X << 28) | (X >> 4)); \
- Y ^= SB7[ (T ) & 0x3F ] ^ \
- SB5[ (T >> 8) & 0x3F ] ^ \
- SB3[ (T >> 16) & 0x3F ] ^ \
- SB1[ (T >> 24) & 0x3F ]; \
-}
+#define DES_ROUND(X,Y) \
+ do \
+ { \
+ T = *SK++ ^ (X); \
+ (Y) ^= SB8[ (T ) & 0x3F ] ^ \
+ SB6[ (T >> 8) & 0x3F ] ^ \
+ SB4[ (T >> 16) & 0x3F ] ^ \
+ SB2[ (T >> 24) & 0x3F ]; \
+ \
+ T = *SK++ ^ (((X) << 28) | ((X) >> 4)); \
+ (Y) ^= SB7[ (T ) & 0x3F ] ^ \
+ SB5[ (T >> 8) & 0x3F ] ^ \
+ SB3[ (T >> 16) & 0x3F ] ^ \
+ SB1[ (T >> 24) & 0x3F ]; \
+ } while( 0 )
-#define SWAP(a,b) { uint32_t t = a; a = b; b = t; t = 0; }
+#define SWAP(a,b) \
+ do \
+ { \
+ uint32_t t = (a); (a) = (b); (b) = t; t = 0; \
+ } while( 0 )
void mbedtls_des_init( mbedtls_des_context *ctx )
{